The present invention relates to a method and apparatus for continuously producing photographic film by perforating the film, applying characters thereto and cutting it.
In the manufacture of 16 mm and 35 mm roll films, the automatic continuous production of film to obtain predetermined lengths of film strip has found widespread acceptance because it contributes to savings in time and labor. As a rule, the process comprises the steps of producing a film web by providing photosensitive emulsion layers on the surface of a flexible, transparent base or film support which is a long, wide web, slitting the film web into narrow film strips, perforating the narrow film strips, applying latent images of characters to the perforated film strips, cutting the perforated film strip into predetermined lengths of film strip which are relatively short, winding each film strip into a container for protection against light, and packaging the containers each including a film strip for shipping, as is more fully disclosed in U.S. Pat. No. 2,940,232 and Japanese patent unexamined publication No. 115,215/77.
In the step of providing photosensitive emulsion layers on the surface of a web-like film support, the film web with photosensitive emulsion layers coated thereon is wound in a roll after drying. The film web in a roll is slit into narrow film strips, while it is rewound and then wound again in rolls. The slit film strip is rewound for perforating along the longitudinal margins thereof, and subsequently characters are applied, for instance frame numbers, symbols, marks and the like (which are herein generically referred to as "characters") as latent images which are later photographically developed during the processing of the exposed film. After the provision of perforations and characters the film strip is again wound in a roll in preparation for the following steps. In the cutting and winding steps, the film web is cut into sized film strips and then put into containers. The containers are then packed in boxes for shipping.
The above film-producing method, however, is disadvantageous in that not only is it difficult to provide a simplified process of film production, but also a large capital investment is required and a reduced rate of production is suffered, because separate machines are used for each step of the process. As a rule, it is necessary in the conventional process to provide the film strip with cutting marks in the step wherein it is provided with characters, which marks are scanned later for cutting the film strip in order to form sized film strips. Furthermore, as the length to which the film web is cut is determined in the step wherein the film strip is provided with characters, it is unavoidable to classify rolled film strips in accordance with the lengths to which they are to be cut if it is desired continuously to manufacture different sizes of film strips. These disadvantages make process control troublesome and the process unsuitable for a diversified small-quantity production line.
There has recently been proposed a photographic film production method which provides a unified step for slitting, perforating and character application, wherein a long strip of photographic film is perforated, provided with characters as latent images, and slit and then rolled, as is fully disclosed in Japanese patent unexamined publication No. 177,137/82. This method is advantageous in order to simplify the process of film production. On the other hand, it has the disadvantages that it is difficult to change the size of film strip to be produced and that it is very difficult to cut the film strip accurately to a predetermined length, because there are no cutting marks.